Working People's Day of Action will take place two days before a major Supreme Court case on unions.

On the eve of oral arguments in one of the most important legal battles in modern labor history, America’s unions plan to take their case to the court of public opinion.

On Feb. 24 — two days before the Supreme Court tackles Janus vs. AFSCME — a massive mobilization hopes to get thousands into the streets in a show of labor strength.

Dubbed the “Working People’s Day of Action,” the nationwide rallies aim to invoke the spirit of the Rev. Martin Luther King Jr. and the sanitation workers who walked off their jobs in Memphis 50 years ago.

It was on Feb. 12, 1968, that the black sanitation workers — carrying signs that said “I Am A Man” — started their high-stakes strike. At the same time, they sought to join Local 1733.

Local 1733 is part of the American Federation of State, County and Municipal Employees — and it’s AFSCME that’s now the defendant in the Janus case that many labor leaders see as a right-wing-funded attempt to deal the union movement a potentially crippling blow.

Baxter Richard Leach, a former protester in the 1968 sanitation strike in Memphis, Tenn., will take part in the rally in New York.

(Fred Nye/Teamsters Joint Council 16)

At stake is the right of public-sector unions to charge fees to workers who choose not to join labor organizations — but who still gain from the collectively bargained salaries, pensions and other benefits that unions negotiate on their behalf.

A loss in the case would overturn about 40 years of established labor law, and possibly put severe strains on the finances of public-sector unions across the country.

Baxter Leach, a longtime AFSCME member and sanitation worker who participated in the 1968 Memphis strike, will take center stage Feb. 24 at Foley Square in lower Manhattan.

Leach, 78, was present when King gave a speech in Memphis March 18 and again when he tried to march with strikers 10 days later.

Dr. Martin Luther King Jr. and Rev. Ralph Abernathy (r.) lead a march on behalf of striking Memphis, Tennessee., sanitation workers on March 28, 1968.

(Sam Melhorn/The Commercial Appeal via AP)

He will be among the many civil rights figures and leaders who attend the New York rally — which organizers expect to draw a crowd of roughly 5,000.

Public- and private-sector labor groups are preparing to turn out — even though the immediate threat of Janus vs. AFSCME is to municipal unions.

“What we want to do is send a powerful message to the rest of the country that here in New York working people clearly understand that the labor movement is the backbone of the middle class,” said Mario Cilento, head of the state AFL-CIO.

“The freedom of working men and women to have a voice in the workplace is under an unprecedented attack by conservative ideologues in Washington backed by powerful corporations. . . . We will not allow these assaults to silence the voice of working people,” he added.

“We’re standing shoulder to shoulder to rise up against those advancing their profits over our progress,” said Jobs With Justice Executive Director Sarita Gupta.

(Chip Somodevilla/Getty Images)

Similar rallies will take place in San Diego; Miami; Detroit; St. Paul; Columbus, Ohio; Philadelphia; Chicago; Memphis, and D.C.

The Working People’s Day of Action was spearheaded by workers' rights organization Jobs With Justice — but its outreach spans a nexus of labor, civil rights, environmental, religious and social justice groups.

“We’re standing shoulder to shoulder to rise up against those advancing their profits over our progress,” said Jobs With Justice Executive Director Sarita Gupta.

“No court, no President and no corporate bully can stop us when enough of us unite for our freedoms to achieve a decent living, equitable workplaces, strong health care, safe communities and a better future,” Gupta said.

Striking sanitation workers and their supporters are flanked by bayonet-wielding National Guard troops and armored vehicles during a march on City Hall in Memphis, Tenn., on March 29, 1968.

(Charlie Kelly/AP)

The case that will be argued before the Supreme Court on Feb. 26 was launched by Mark Janus, a government employee in Illinois.

Janus has argued that he doesn’t agree with AFSCME’s political positions and that he should not be forced to pay fees to support the union — even though it collectively bargains and protects Illinois state employees, including him.

Backed by numerous conservative and right-to-work groups, Janus sued the union for abridging his First Amendment rights — even though — thanks to an existing law — he can get a refund from the union for any of his dues money that is spent on political campaigns.